Desulfurization renovation project using a circulating fluidized bed for the flue gas of the 130T/h boiler at Chifeng Thermal Power Plant

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The simple wet flue gas desulfurization technology is a wet flue gas desulfurization method developed by Colin Environmental Protection Engineering Co., Ltd. based on the introduction of Canadian technology, combined with traditional wet desulfurization techniques, to suit China’s national conditions. The desulfurization principle of this technology is exactly the same as that of traditional wet desulfurization. By simplifying the desulfurizer grinding system, by-product treatment system, peroxide system, and flue gas reheating system, its engineering investment cost is less than 50% of that of conventional wet desulfurization projects. The development of this technology addresses issues such as the high initial investment and complex operation requirements of traditional wet flue gas desulfurization methods, and can meet the economic and efficient desulfurization needs of power plants in China. In the process, the flue gas is cleaned of dust using an electrostatic precipitator, and then it enters the desulfurization tower via an exhaust fan. There, chemical reactions occur as a result of gas-liquid contact and interaction with the spray liquid containing a desulfurizing agent, thereby removing SO2 from the flue gas. The clean flue gas passes through a demister to remove the water mist contained in it, and is then discharged after being mixed and heated. The desulfurization agent is quicklime CaO, which, after being thoroughly digested and mixed, enters the circulation pool at the bottom of the desulfurization tower; from there, it is pumped into the tower via a circulation pump to participate in the desulfurization reaction. The by-products of the desulfurization reaction undergo an oxidation reaction with the air blown in by the oxidation fan to form gypsum; after being mixed evenly, it is discharged through a sewage pump for further treatment. Process principle • After being digested in the digestion tank, the desulfurization agent is pumped by a slurry transfer pump into the circulation pool of the desulfurization tower ； •The slurry containing desulfurizing agent in the tower is pumped by a circulation pump to the desulfurization nozzle ； •In the desulfurization tower, multiple layers of nozzles create multiple water films from top to bottom, which come into contact with the smoke moving upward, absorb it, and undergo reactions, thereby removing SO2 from the smoke ； •The desulfurization by-product slurry is discharged into a concentration tank, where it undergoes concentration and filtration; the supernatant can be reused. Reaction mechanisms:
CaO + SO2 + 1/2H2O → CaSO3·1/2H2O
Ca(OH)2 + SO2 + 1/2H2O → CaSO3·1/2H2O + H2O
CaSO3·1/2H2O + SO2 + 1/2H2O → Ca(HSO3)2
2CaSO3·1/2H2O + O2 + 2H2O → 2CaSO4·2H2O

Technical features: • The desulfurization efficiency of the desulfurization tower is greater than 90%, while the overall system desulfurization efficiency is greater than 85% ； •Low cost, with low initial investment and operating expenses ； •The system's power consumption is significantly reduced compared to traditional wet methods ； •The desulfurization equipment has a compact structure and requires little space for installation ； •A hot flue gas mixing device is used, eliminating the need for a conventional gas-to-gas heat exchanger ； •System availability greater than 95% Technical and economic indicators • Calcium-sulfur ratio (Ca/S)